Mineral Evolution Database
Created and maintained by the Mineral Evolution Project in partnership with RRUFF and mindat.
Mineral locality data provided by mindat.org

Ages for Montmorillonite at Keystone, Keystone District, Pennington Co., South Dakota, USA

The cyan highlights indicate which age entries were selected as the "best" for assigning the mineral an age of 1700Ma - 1640Ma at this locality

Age range from children

Excel ID	Max Age (Ma)	Min Age (Ma)	Dated Mineral	Minerals explicitely stated as having this age	Age applies to these Elements	Dated Locality ID	Dated Locality	Ref	Ref ID
Alexandra-0372	1700	1700			Li,Be,Sn,Cs,Ta,Nb,U	122418	Black Elk Peak (Harney Peak), Pennington Co., South Dakota, USA	Norton and Redden (1990)	AM75_631
Alexandra-0270	1640	1640	Muscovite			4106	Etta Mine, Keystone, Keystone District, Pennington Co., South Dakota, USA	Riley (1970)	GCA34_713

Locality age

Excel ID	Max Age (Ma)	Min Age (Ma)	Dated Mineral	Minerals explicitely stated as having this age	Age applies to these Elements	Dated Locality ID	Dated Locality	Ref	Ref ID
Alexandra-0270	1640	1640	Muscovite			4106	Etta Mine, Keystone, Keystone District, Pennington Co., South Dakota, USA	Riley (1970)	GCA34_713
USGS-Rb-Sr-00189	1783.5	1603.5	Muscovite			8771	Bob Ingersoll Mine (Ingersoll Mine; Ben Butler Mine; Horace Greely Mine), Keystone, Keystone District, Pennington Co., South Dakota, USA	USGS-Rb-Sr	USGS-Rb-Sr
USGS-Rb-Sr-00190	1695.19	1535.19				8771	Bob Ingersoll Mine (Ingersoll Mine; Ben Butler Mine; Horace Greely Mine), Keystone, Keystone District, Pennington Co., South Dakota, USA	USGS-Rb-Sr	USGS-Rb-Sr
USGS-Rb-Sr-00424	1585.82	1585.82				8771	Bob Ingersoll Mine (Ingersoll Mine; Ben Butler Mine; Horace Greely Mine), Keystone, Keystone District, Pennington Co., South Dakota, USA	USGS-Rb-Sr	USGS-Rb-Sr
USGS-U-Th-Pb-00031_206_238	1648.5	1488.5				8771	Bob Ingersoll Mine (Ingersoll Mine; Ben Butler Mine; Horace Greely Mine), Keystone, Keystone District, Pennington Co., South Dakota, USA	USGS-U-Th-Pb	USGS-U-Th-Pb
USGS-U-Th-Pb-00031_207_206	1673.5	1513.5				8771	Bob Ingersoll Mine (Ingersoll Mine; Ben Butler Mine; Horace Greely Mine), Keystone, Keystone District, Pennington Co., South Dakota, USA	USGS-U-Th-Pb	USGS-U-Th-Pb
USGS-U-Th-Pb-00031_207_235	1659.2	1499.2				8771	Bob Ingersoll Mine (Ingersoll Mine; Ben Butler Mine; Horace Greely Mine), Keystone, Keystone District, Pennington Co., South Dakota, USA	USGS-U-Th-Pb	USGS-U-Th-Pb
USGS-U-Th-Pb-00211_206_238	1608.2	1598.2				8771	Bob Ingersoll Mine (Ingersoll Mine; Ben Butler Mine; Horace Greely Mine), Keystone, Keystone District, Pennington Co., South Dakota, USA	USGS-U-Th-Pb	USGS-U-Th-Pb
USGS-U-Th-Pb-00211_207_206	1591.9	1571.9				8771	Bob Ingersoll Mine (Ingersoll Mine; Ben Butler Mine; Horace Greely Mine), Keystone, Keystone District, Pennington Co., South Dakota, USA	USGS-U-Th-Pb	USGS-U-Th-Pb
USGS-U-Th-Pb-00211_207_235	1599	1589				8771	Bob Ingersoll Mine (Ingersoll Mine; Ben Butler Mine; Horace Greely Mine), Keystone, Keystone District, Pennington Co., South Dakota, USA	USGS-U-Th-Pb	USGS-U-Th-Pb
USGS-U-Th-Pb-00212_206_238	1384.9	1374.9				8771	Bob Ingersoll Mine (Ingersoll Mine; Ben Butler Mine; Horace Greely Mine), Keystone, Keystone District, Pennington Co., South Dakota, USA	USGS-U-Th-Pb	USGS-U-Th-Pb
USGS-U-Th-Pb-00212_207_206	1547.4	1517.4				8771	Bob Ingersoll Mine (Ingersoll Mine; Ben Butler Mine; Horace Greely Mine), Keystone, Keystone District, Pennington Co., South Dakota, USA	USGS-U-Th-Pb	USGS-U-Th-Pb
USGS-U-Th-Pb-00212_207_235	1446	1436				8771	Bob Ingersoll Mine (Ingersoll Mine; Ben Butler Mine; Horace Greely Mine), Keystone, Keystone District, Pennington Co., South Dakota, USA	USGS-U-Th-Pb	USGS-U-Th-Pb

Locality age (remote)

Excel ID	Max Age (Ma)	Min Age (Ma)	Dated Mineral	Minerals explicitely stated as having this age	Age applies to these Elements	Dated Locality ID	Dated Locality	Ref	Ref ID
Alexandra-0372	1700	1700			Li,Be,Sn,Cs,Ta,Nb,U	122418	Black Elk Peak (Harney Peak), Pennington Co., South Dakota, USA	Norton and Redden (1990)	AM75_631